Download

ISPRS 2003 The role of Synthetic Aperture Radar in Extraterrestrial Mapping

Most of the surfaces of Mercury, the Moon and Mars are covered by regolith, a large part of which has been generated by repeated hypervelocity impact resulting in the widespread redistribution of materials. On some planets (Mars), aeolian effects have further redistributed the finer particulates. As a result, the solid in situ bedrock of these planetary bodies is obscured. Yet for geologists, determining the solid geology of a given planet is key to establishing its geological evolution and for selecting landing sites for bedrock sampling. Unfortunately, details of the solid surface beneath the regolith are not revealed by optical techniques, although the latter help tremendously with regard to understanding a planet’s morphology, from which aspects of the underlying solid geology can be inferred. The true nature and thickness of the regolith, and the proximity of bedrock and sub-surface ice or liquid water can only be detected and mapped by an instrument capable of probing at different penetration depths beneath the surface. This includes identifying ice, or features that reveal the presence of ice. Synthetic Aperture Radar (SAR), especially at lower microwave frequencies, is suited for such an endeavour.